checkpoint 2

Author: cadenmyers13

tests/conftest.py

@@ -24,6 +24,10 @@ def user_filesystem(tmp_path):
     )
     binary_data = b"\x00\x01\x02\x03\x04"
 
+    with open(base_dir / "data.chi", "w") as f:
+        f.write(chi_data)
+    with open(base_dir / "data_corrected.chi", "w") as f:
+        f.write(chi_data)
     with open(base_dir / "good_data.chi", "w") as f:
         f.write(chi_data)
     with open(base_dir / "good_data.xy", "w") as f:

tests/test_labpdfprocapp.py

@@ -0,0 +1,27 @@
+import pytest
+
+from diffpy.labpdfproc.labpdfprocapp import (
+    apply_absorption_correction,
+    get_args_cli,
+)
+
+
+# Case: user tries to run absorption correction, but the output
+# filename already exists.
+# expected: the function should raise a FileExistsError, telling the
+# user that the output
+# file already exists and asking if they want to overwrite it.
+def test_file_exists_error(user_filesystem):
+    input_data_file = str(user_filesystem / "data.chi")
+    existing_corrected_file = str(user_filesystem / "data_corrected.chi")
+
+    cli_inputs = ["mud"] + [input_data_file] + ["2.5"]
+    args = get_args_cli(cli_inputs)
+    # assert args == []
+    msg = (
+        "The following output files already exist:"
+        f"\n{existing_corrected_file}\n"
+        "Use --force to overwrite them."
+    )
+    with pytest.raises(FileExistsError, match=msg):
+        apply_absorption_correction(args)